Categorical Imperative

The 'Categorical Imperative (CI)' is the central principle of Immanuel Kant's moral philosophy. It is used to test maxims—subjective principles of action—for their moral permissibility. Here, the imperative functions as an exclusion procedure to find principles that are without exception and at the same time universal. Hence categorical.

Only those maxims that withstand a specific test may be followed. It does not show what is morally required, but rather what is not morally allowed. Within this, a broader realm of morally permissible actions is formed, allowing for individual discretion. The neutral.

I pondered a bit whether the categorical imperative actually marks a worldview or rather represents a myth. What do you think? Write to me or use the +ZEITGESCHENK so we can explore this together.

Kant formulates his 'Categorical Imperative' in three equivalent, complementary versions that, when applied correctly, should always lead to the same moral judgment:

Fundamental Formula (Formula of Universal Law)

Act only according to that maxim whereby you can at the same time will that it should become a universal law.

→ This version tests the logical consistency of a maxim when generalized. It asks: Can I will that everyone in the same situation acts as I do?

Humanity as an End Formula

Act so that you treat humanity, whether in your own person or in the person of any other, always at the same time as an end and never merely as a means.

→ This formula emphasizes the dignity of humans, who are considered ends in themselves. It poses the question: Do I respect the autonomy of all involved, or do I merely use others for my purposes?

Kingdom of Ends Formula (Realm of Purpose)

Act according to maxims that can come together in a possible kingdom of ends as a realm of nature.

→ This version examines the coherence of all maxims concerning a universal, autonomous co-existence. It questions: Could everyone live self-determined and dignified lives under these rules?

Overall, the 'Categorical Imperative' represents a standard of rational morality based on autonomy, universality, and respect for humans as an end in themselves.

Adaptations in the Theory of Practical Reason

Anyone who does not want to see an escape in the categorical imperative might turn to the theory of practical reason →. Julian Nida-Rümelin's theory of practical reason adopts Kant's categorical imperative but fundamentally modifies it by integrating it into the concept of structural rationality.

While Kant justifies the categorical imperative as an unconditional, formal principle of morality that measures actions solely by their universalizability, Nida-Rümelin emphasizes the integration of actions into broader practical structures legitimized through Deliberation and weighing of reasons.

A scene in the film 'Irrational Man' featuring Joaquin Phoenix and Emma Stone makes the difference more accessible. In a dialogue →, Kant's categorical imperative and its absolute stance on truthfulness are critically discussed. The course of the conversation shows the following argumentation.

According to Kant's view, in a morally perfect world, there would be absolutely no room for lies, as even the smallest falsehood would undermine the categorical imperative.

This is illustrated by two examples. Once, a murderer asks about the whereabouts of his hidden victim—according to Kant, one would have to answer truthfully. While some might rationally maneuver out of the situation as to why they would lie in this case, the second example highlights the extreme case. The Nazis ask about the hidden Anne Frank and her family—here too, Kant's strict interpretation would demand telling the truth.

The scene in the film shows the problematic consequences of a too rigid application of the categorical imperative, which is also addressed by Nida-Rümelin's later criticism. He argues for a more flexible approach that better accounts for complex action contexts. Thus, worldviews and ideologies can be examined within the framework of Cultural Foresight →.

Core Differences to Kant's Position

Structural Rationality vs. formal maxim testing

Nida-Rümelin criticizes that Kant's imperative is too rigid to capture complex action contexts. Instead of universal maxims, he calls for a rationality that evaluates actions based on their fit into desirable practical forms—such as just institutions or coherent life plans.

Example: A lie might formally fail under Kant, but be permissible under Nida-Rümelin if it is part of a structurally intact communication practice.

Reasons as propositional contents

In contrast to Kant's autonomy of reason, Nida-Rümelin grounds practical reasons in an intersubjective practice of justification5. Moral norms do not arise from purely rational self-legislation, but from the ability to reflect distantly on shared conditions of action.

Critique of the optimization paradigm

Nida-Rümelin rejects both Kant's deontological strictness and consequentialist calculations. Instead of "maximizing the good" or "duty for duty's sake," he focuses on the coherence of action patterns35. An action is rational if it fits into a reasonable practice—even if it is neither optimal nor dutiful.

Commonalities with Kant

• Both emphasize the ability to distance oneself from immediate inclinations.

• The idea of universalizability remains, but is contextualized: Not maxims, but forms of practice must be universally justifiable5.

• Both reject a reductionist naturalism and insist on the peculiar logic of practical reason.

Nida-Rümelin's approach can be read as a synthetic advancement: It preserves Kant's insight into the normativity of reason, but overcomes its abstract rigorism with a practice-oriented theory of rationality.